The invention relates to an air filter, especially an air intake filter for internal combustion engines.
U.S. Pat. No. 4,006,000 discloses an air filter for filtering intake air, with a substantially cylindrical housing which has a raw air inlet that is arranged tangentially on the housing, and in this housing is a filter insert through which air flows radially.
The housing itself can be attached with a bayonet lock to a cylindrical air intake collector. In this intake air collector is a safety cartridge which is intended to prevent the entry of dust and dirt into the air intake connection when the filter insert is changed.
A seal is created between the safety cartridge and the filter insert because, after the bayonet lock is engaged, the filter insert is axially displaced toward the safety cartridge, through which the end face of the filter insert comes in contact with the end face of the safety cartridge.
This axial displacement is performed with an adjusting screw disposed on the end wall of the housing, which exerts an axial movement on the end plate of the filter insert.
A disadvantage of this known device is that a very large free space must be present around the housing for the insertion and removal of the filter insert.
Initially, in order to release the bayonet lock, a certain axial movement must be possible. On the other hand, the necessary rotation of the adjusting screw for the axial displacement of the filter insert is possible only if sufficient space is provided in the vicinity of this adjusting screw for manual access to it. This type of construction of an air intake filter is therefore unsuitable where space is restricted.
German Patent 39 18 347, (corresponding to U.S. Pat. No. 5,042,999) discloses an air intake filter for an internal combustion engine, in which only a short axial movement of the housing is necessary for installation and removal. For this purpose a filter pot is provided which is inserted into a sliding shoe and can be fastened by means of a tilting movement to a part that receives it.
Although exchanging the filter element is possible here within very limited space, there exists the danger that, in case of shaking or vibration the housing may undergo resonance vibrations, and sealing problems may occur.